The invention relates to a bottle-bearing plate with a centering device, in a labeling machine. In particular the invention is applicable to the labeling of bottles having very concave bases and therefore not presenting a large base surface on which they can adhere on a rest plane or a plate. Such bottles are provided with a reference recess sunk into the bottle base surface, but the recess is limited in radial length due to the very concave shape of the bottle base.
High-speed labeling machines generally comprise a platform, known as a turntable, which rotates about a central vertical axis. Labeling, smoothing and brushing stations are positioned about the turntable.
On the platform of the machine, a plurality of plates are mounted which can rotate about themselves, and onto which the bottles or containers are transported by a star conveyor.
The rotation of the plates is used to position the bottles at a determined position with respect to the labeling stations so that the labels can be positioned at a precise position on the bottles. Prior art centering devices, especially those for the above-described type of bottle, usually exhibit plates having an internal pad which acts on the base of the bottle.
Centering devices of this type present only a small blocking surface for the bottle, leaving the bottle prone to angular movements, leading to possibly incorrect label positioning.
A further drawback is due to the fact that the bottles almost always exhibit milling or ribbing around the base, which lead to considerable wear on the generally rubber pad.